1. Field of the Invention
The invention relates to operators for slidable windows such as double-hung windows, and more particularly relates to a handcrank-operated power transmitting window operator which can be retrofitted on an existing window or included in a new window installation, at the side, out of view.
2. Description of Related Art
Double-hung windows predominate in residential and small business structures built during the past hundred years. In the classic double-hung window, there is an upper sash and a lower sash separated by a wooden strip so as to slide independently of each other. The upper sash is usually outside, to shed water. Upper sash and lower sash are independently counterbalanced by weights cord-supported over pulleys in the window frame. Wooden double-hung windows in many older structures are reaching their limits of age. Many are being replaced by aluminum sashes mounted in channels to fit where the older wooden sash was allowed to slide. Double-hung aluminum windows typically tilt in for washing; they are held within the channels by lateral extensions which are moved out of the channel to allow tilting. The replacement window may have spring counterweights within the channels. The replacement window is expected to fit more closely than the wooden sash ever did, to fulfill modern temperature control requirements. This tighter fit, and the absence of free-running counterweights, can make the replacement window difficult to operate.
A window operator technology was developed during the heyday of the wooden sash double-hung window, to control easy raising and lowering, locking and access for washing or repair. Exemplary of this technology the following: U.S. Pat. No. 1,152,425, Lovell, WINDOW OPERATING APPARATUS, Sep. 7, 1915, provides a geared crank at the base of the window. The crank turns a base shaft which through bevel gears turns a pair of vertical spiral worm shafts, one worm shaft on each side of the window, for each sash. There are four vertical worm shafts for each double-hung window. Turning the crank opens or closes both top and bottom sashes equally and simultaneously.
U.S. Pat. No. 1,271,717, Kaufman, BELT GUARD, Jul. 9, 1918, shows a belt guard for a fan belt in a Model T Ford. The belt guard constrains the belt within a rectangular opening as a guide to keep the belt from flopping off its pulleys.
U.S. Pat. No. 1,590,473, Miller, WINDOW OPERATING APPARATUS, Jun. 29, 1926, shows a balanced cable-drive window operator. Cable spools at each side of the double-hung window are crank-operated to raise the bottom sash and lower the top sash simultaneously.
U.S. Pat. No. 1,854,419, Neuhausen, WINDOW CONSTRUCTION, Apr. 19, 1932, shows a mechanism permitting a double-hung window to be opened normally, or to be swung open for cleaning or repair.
U.S. Pat. No. 2,012,386, Genberg, SLIDING WINDOW, Aug. 27, 1935, shows a mechanism for holding top and bottom sashes aligned in the same plane when the window is closed, offsetting the top and bottom sashes to open the window.
U.S. Pat. No. 2,026,119, Bentzenberg, WINDOW CONSTRUCTION, Dec. 31, 1935, also shows mechanism to offset upper and lower sashes.
U.S. Pat. No. 2,399,109, Geer, WINDOW, Apr. 23, 1946, shows a unit window in which the operator mechanism, a crank-driven rack and pinion gear set, is factory installed, with mechanism to move the window sash laterally away from its mating window sash for easier operation.
U.S. Pat. No. 2,545,449, Curley, OPERATING MECHANISM FOR A WINDOW AND CASING ASSEMBLY, Mar. 20, 1951, shows crank-operated horizontal shaft power train bevel-gear-connected to a pair of worm gears which operate the window sash.
U.S. Pat. No. 2,649,301, Signore, WINDOW SASH OPERATING MECHANISM, Aug. 18, 1953, shows a crank-operated horizontal shaft and balanced rack and pinion gear sets to operate the window sash.
U.S. Pat. No. 3,022,065, Martin, POWER APPARATUS FOR WINDOWS AND THE LIKE, Feb. 20, 1962, shows control mechanisms for connecting a motor to a drive rod for operating a double-hung window.
U.S. Pat. No. 3,152,368, Stuart, SLIDING WINDOWS WITH OPERATORS THEREFOR, Oct. 13, 1964, shows a crank-operated mechanism for operating sliding windows by a rack and pinion gear set.
U.S. Pat. No. 3,324,594, Hettinger et al, POWER APPARATUS FOR WINDOWS OR THE LIKE, Jun. 13, 1967, shows a motorized rack and pinion mechanism for positioning the sash directly.
U.S. Pat. No. 4,020,593, Salomon et al, WINDOW WINDING APPARATUS FOR VERTICALLY DIVIDED AUTOMOBILE SLIDING WINDOW PANES, May 3, 1977, shows a constrained cable which moves connector studs within slide channels attached to both the small triangular window and larger window on a front door, to operate the triangular window and the larger window simultaneously as the respective connector studs follow descending and ascending loops.
U.S. Pat. No. 4,306,378, Fukura et al, WINDOW REGULATOR FOR AUTOMOTIVE VEHICLES, Dec. 22, 1981, shows an auto window mounted in a guide rail set and operated by a reciprocal wire over pulleys above and below the limit of travel for the connection between wire and window.
U.S. Pat. No. 4,353,185, Saigne, WINDOW RAISER, Oct. 12, 1982, shows a screw jack for an automobile window, in which two crossed arms are fixed to the window and to a wormscrew at their crossing, with free ends sliding in a horizontally fixed channel; the jack is in X configuration which collapses or extends to lower or raise the window.
U.S. Pat. No. 4,660,325, Bauer et al, FLEXIBLE WINDOW REGULATOR ASSEMBLY, Apr. 28, 1987, shows a balanced stiff tape system to deliver rotary power with mechanical advantage to a reciprocating window. The tape carries rotary motion from a motor or crank operated drum to a reciprocating reach of tape between rounded guides so that there is a reach of tape in line with and coextensive to the travel of the window. The window is connected to the tape by a carrier plate which has jaws to clamp it to the tape, which drives the window up or down.
U.S. Pat. No. 4,793,099, Frieze et al, TAPE DRIVEN POWER WINDOW MODULE, Dec. 27, 1988, shows a replacement module for a fixed rear window of a pickup truck. The replacement module adds the feature of opening of the window, with both window and operating mechanism included in the module. The window is balanced by resilient bands which overcome the weight and friction of the window to keep the window relatively weightless. The window is raised and lowered by gear driven balanced slotted tapes which pull down or push up the window under urging from a crank or motor. Tapes are constricted in channels to keep the tapes from collapsing when actually pushing the window up. The tape either permits the window to rise under urging of a positive counterbalance force, or actually pushes the window sash upward, the tape being constrained in a tight channel.
The prior art thus shows simple and complex techniques for crank operation of double-hung or other slidable windows, generally using a balanced approach with lifting power applied equally to each side of the sash. The prior art, however, has not solved window operator problems inherent in the window replacement market, in which the wooden sash sliding easily on counterweights is replaced by an aluminum sash with spring or friction operation. The prior art has not fully dealt with the problems of retrofitting a window operator onto an existing wooden or aluminum sash.